Bios questions of AI7

I've no idea what the following bios items are:
Videa BIOS Casheable
Memory Hole at 15M-16M
Delay Prior to Thermal
AGP Aperture size

What value should I set for these bios items?
Should I set the AGP Aperture size to the memory size of the display card?
Is there any thread discuss these things before?
Thx for any help.

The old rule of thumb is to set the AGP aperature at the same size as your vid card memory, although nowadays, it seems to be good to set it at the next highest value above your vid card RAM. I leave the rest of those on default.